This invention relates to apparatus for actuating hydrofoil flaps. More particularly, this invention relates to a control rod system for transferring actuator induced forces to a hydrofoil flap.
Hydrofoil craft generally include three or more struts that extend downwardly from the hull. At the lower end of the struts, hydrofoils are fixed to extend substantially orthogonal to the struts. When the craft reaches an appropriate speed, the hydrodynamic properties of the hydrofoil cause the hull to be lifted out of the water, leaving the craft "flying" on its hydrofoils.
To control the attitude of the craft as it moves through the water, flaps are attached to the trailing edges of hydrofoils. Movement of the flaps is controlled by an actuator that is located within the hull. A control rod is connected between the actuator and the flap for communicating the push and pull forces generated by the actuator to the flap. Current hydrofoil control rod systems employ control rods having circular cross sections that are housed within cylindrical guide tubes. Spacers or bushings mounted in the guide tube support the rod within the guide tube. Proper operation of the rod within the tube requires that the rod and tube be carefully machined and assembled to maintain accurate, concentric alignment. Furthermore, once the tubes are affixed to the strut, access to the rod for replacement or repair requires axial clearance (either above or below the guide tube) that is at least equal to the length of the rod; a problematic space requirement for typical repair facilities.